Systematic Reviews and Meta AnalysisMeta-analysis of well-designed nonrandomized comparative studies of surgical procedures is as good as randomized controlled trials
Section snippets
Background
It has been argued that nonrandomized comparative studies (NRCSs) of intervention could either exaggerate or underestimate the measured magnitude of effect size [1]. However, it has also been argued that if they were well-designed cohort studies, they were more likely to be in agreement with randomized controlled trials (RCTs) than other observational studies [1]. Furthermore, and given the paucity of and the difficulties associated with conducting RCTs of surgical procedures, the absolute need
Methods
Two meta-analyses comparing the short-term outcomes after laparoscopic resection (LR) vs. conventional open resection (COR) for colorectal cancer (CRC) in RCTs and NRCSs were conducted according to accepted standards. Details of selection criteria, MeSH terms, databases used in literature search, and period of search have been published elsewhere [2], [3]. The results of these two meta-analyses were compared.
Critical appraisal
Summary of critical appraisal for the RCTs is provided in Table 1 and for the NRCSs in Tables 2. The total quality scores for the RCTs ranged from 4 to 8 out of 11 with a mean (SD) of 6.3 (1.2). For the NRCSs, the quality scores ranged from 10 to 23 out of 24 with a mean (SD) of 16.4 (2.6).
Collated data analysis
For all three dichotomous outcomes, namely mortality, reoperation, and early morbidity rates, the OR in the meta-analysis of the NRCSs overlapped widely with that of the RCTs (Fig. 1).
Morbidity rates
In the meta-analysis of
Discussion and conclusions
Although it has been argued that the results of systematic reviews of observational studies cannot be considered definitive and should be interpreted with caution [10], the results of the current meta-analysis of NRCSs of the short-term outcomes after LR vs. COR for CRC published in the English-language literature by the end of 2003 were remarkably similar to the meta-analysis of RCTs published by the end of 2002.
Reviews of evidence derived from NRCSs of medical interventions have yielded
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